JPS59198822A - Solid cable line - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Technical field The present invention changes the structure of the line of the electric power cable.

Conventional technology For example, 30 to 40 km of ultra-high voltage such as 275 KV
For the above long submarine cables, OF cables are not suitable because it is difficult to supply insulating oil from both ends. Therefore, instead of the OF cable, a solid insulated oil cable impregnated with bad insulating oil has been used. Solid insulated oil cables are made by impregnating the insulating layer around the cable conductor with insulating oil, which is non-fluid and highly viscous in the temperature range of 50° to 60° C. or lower, at the time of factory manufacturing. However, when this type of solid insulated oil cable is used for a long submarine cable, the insulating oil becomes fluid due to the rise in temperature caused by use, and if there are height differences in the cable installation route, some of the insulating oil may become fluid. The problem is that the insulating oil in high places dries up and the so-called "oil dripping phenomenon" occurs, and the dielectric strength of the parts where the insulating oil has drained deteriorates. The drawback was that the power transmission system could not be designed.

On the other hand, when connecting solid insulated oil cables as described above using an appropriate junction box, the cables are laid without paying attention to the height of the cable installation path, and the junction box is placed at a higher position than the cables. When this happens, the insulating oil in the junction box flows toward the cable side, causing oil dripping near the junction box. Generally speaking, the connection part, which has a weaker dielectric strength than the cable, becomes the weak point, and the terminal end is a problem where the dielectric strength of the cable cable line in question decreases. occurs.

Purpose This invention eliminates the above-mentioned drawbacks, effectively prevents the oil dripping phenomenon at the connection part of a solid cable, prevents a decrease in dielectric strength, enables stable high-voltage power transmission, and reduces installation costs. The purpose of the present invention is to provide an electric cable line that can be inexpensive.

EXAMPLE An example of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, 1 is, for example, 275 KV2-1
．． 2-2. ......, 2-(n-1), 2
-n are solid cables in which an insulating layer (not shown) covering a cable conductor core (not shown) is impregnated with a grease-like solid insulating oil at a temperature of 50°C to 60°C, and each is, for example, l It has a length of about 5 km to 5 km. These solid cables 2-1.
2-2. . . . , 2-n are laid by a known method so as to extend approximately horizontally at appropriate depths underground, and each solid cable is installed in a known intermediate junction box. 3-1. :3-2°...-..., connected in series via 3-n. Each intermediate junction box, for example 3-1, is installed at a position lower than the installation position of any of the solid cables 2-1 and 2-2 connected to the junction box.

Similarly, other intermediate junction boxes 3-2, 3-3,...
..., 3-n is also installed at a position lower than the laying position of any of the connected solid cables on both sides.

Reference numeral 4 denotes a power transmission side terminal connection box connected to the solid cable 2-1, and 5 denotes a power reception side termination connection box connected to the solid cable 2-n. These junction boxes 4
and 5, for example, a known gas termination connection box or air termination connection box filled with sulfur hexafluoride gas SF6 is used. Both junction boxes 4 and 5 are installed at positions lower than the installation positions of solid cables 2-1 and 2-n, respectively, in the same manner as the intermediate junction boxes described above. That is, both solid cables 2-1 and 2-n are
They are connected in a so-called upside-down end format.

However, if it is not possible to adopt an inverted end due to line conditions, it is necessary to adopt a conventional termination connection in which the termination connection is located above the cable line as shown in FIG. 3'.

In this case, an insulating oil stop joint should be placed near the terminal connection, and an OF cable or a cable with a proven track record of stably maintaining high dielectric strength should be placed near the terminal connection. In the case of cables, prevent a drop in dielectric strength due to oil dripping from the terminal connection.

In the power cable line 1 having the above configuration, the cable temperature rises during power transmission, and each solid cable 2-1. 2
-2. Even if the viscosity of the solid insulating oil of the insulating layer (not shown) in 2-n decreases, each connection box 4. 3-1. 3-2.・・・・・・13”
1 and 5 are each located at a lower position than the installation position of each cable, so these insulating oils can flow toward each connection box, but are prevented from flowing out from each connection box. be able to. Therefore, each solid cable 2
-1. 2-2. . . . , it is possible to prevent cracking in the insulating layer of the connection portion 2-n.

Therefore, the electrical dielectric strength of each connection portion does not decrease, and high voltage power can be stably transmitted. In addition, as mentioned above, since the fluidized insulating oil flows into the connection part of each solid cable, each connection box 3
-1. 3-2. As 3-n, for example, as shown in FIG. 2, a non-lubrication type junction box that is simple in structure and inexpensive can be used.

In addition, when using a stop joint near the terminal connection part described above, in the connection box shown in FIG. By crimping the sleeve 12, when the conductor 10 and the solid conductor 11 are electrically connected, the insulating oil that seeps through the conductor 10 of the solid cable 2 is prevented from flowing out from the solid conductor 11. Make sure that the insulating oil on both sides of the stop joint does not get mixed in.

Furthermore, since an insulating layer 15 is formed between the insulating layer 13 of each solid cable 2 and the hardened composure layer 14 formed to surround the solid conductor 11, even if the insulating layer is passed through, The insulating oil is designed not to mix. 16 is a steel pipe that seals the connection.

In addition, the solenoid IJ-end cable 2-1. 2-2. . . . , 2-n, preferably each connection box 4; 3-1. 3-2.・
.......

3-n, 5, and an insulating layer that covers the part of the cable conductor that is laid down in a hanging manner (see Figure 2).
It is impregnated with a synthetic insulating oil such as solid insulating oil, which has low viscosity and high dielectric strength, such as a synthetic insulating oil such as dodecyl benzene, or an insulating oil mixed with mineral oil. This allows each junction box 4.3-1.3- of the solid cable to
2.・・・・・・・・・

It is possible to more reliably prevent the insulating portion from cracking at the connection portions 3-n and 5, prevent deterioration of the dielectric strength of each connection portion, and stably transmit high voltage power.

Furthermore, the electric cable line 1 is not limited to a line laid underground as in the above-described embodiments, but can be used as an underwater cable line, for example. In particular, when used as a long-distance submarine cable line with DC 300 KV or less, compared to lines using conventional OF cables, it is (a) non-lubricated, small (because no oil passage is required), and (
c) The insulating layer is impregnated with high viscosity insulating oil and there is no oil passage, so there is little chance of seawater getting in. b)) It has excellent advantages such as easy maintenance, inspection, repair, etc. be.

As explained above, according to the present invention, each junction box to which a plurality of solid cables of appropriate lengths are connected is placed at a lower location than the installation position of the solid cables connected to the junction box. Even if the solid insulating oil of each solid cable becomes fluidized when the cable cable line is used, it is possible to reliably prevent the insulating oil from flowing out from the low-lying connections. . Therefore, it is possible to reliably prevent the insulation portion from cracking at each connection portion, and to maintain the dielectric strength of each connection portion at a stable high value, thereby stably transmitting high voltage power. In addition, if the terminal connection part must be located above the terminal end,
Since the cable connected to the terminal connection part can be an OF cable or CV cable with high insulation performance, high quality can be stably maintained over the entire line.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing one embodiment of the present invention, and FIG. 2 is a diagram showing an embodiment of the present invention.
FIG. 3 is a sectional view showing an example of an oil flow prevention type junction box that can be used for the electric power cable line shown in the figure, and FIG. 3 is a diagram showing the main part configuration of the electric power cable line of another embodiment. 1... Electric cable line, 2-1.2-2.・・・・・・
.... 2-n...solid cable, 3-1. :3-2
．．・・・・・・・・・3-n...Intermediate connection box, 4,5...Terminal connection box, 6
...Upward connection type terminal connection box, 8...OF cable. or CV cable patent applicant Sumitomo Electric Industries Co., Ltd. Patent attorney Aoyama Hogai 1 person

Claims (3)

[Claims] (1) Connect multiple solid insulating oil-impregnated Kelpuls of appropriate length via a junction box, and check that each junction box is installed at a lower position than the installation position of the solid cable connected to the junction box. Features a solid cable track. (2) If the solid cable line has an air termination or a gas termination, place an oil stopper junction box near the termination to separate the solid cable from the termination, and connect the OF cable or CV to the termination. A solid cable track characterized by connected cables. (3) The solid cable line according to claim 1, wherein the solid cable near each junction box is impregnated with low-viscosity insulating oil such as DDB or polybutene, which is in a fluid state even at room temperature.